In his New Year's message, the president of the International Olympic Committee condemned what he called "cowardly terrorist attacks" on the main railway station of Volgograd and on a city trolleybus which killed 34 people and wounded scores.

Volgograd is about 650 kilometers (400 miles) northeast of Sochi, which will host the Olympics from Feb. 7-23.

Russian authorities believe the two attacks were carried out by the same group but no one has claimed responsibility for the bombings, which came several months after Chechen rebel leader Doku Umarov threatened new attacks against civilian targets in Russia, including the Olympics.

"We trust that the Russian authorities will deliver safe and secure Olympic Winter Games for all athletes and all participants," Bach said.

Bach also said the Sochi Games "should be a demonstration of unity in diversity and of remarkable athletic achievements - not a platform for politics or division."

The Russian government has been criticized for a new law against gay "propaganda" that has provoked an international backlash, but Russia has given the IOC reassurances it will comply fully with the Olympic Charter's provision against discrimination of any kind in Sochi.

In the fight against doping, Bach said the IOC increased the number of pre-competition tests for Sochi by 57 percent compared to the Vancouver Olympics in 2010.